HONOLULU (KHON2) — Flight delays, stranding thousands across the country Tuesday. And it could get even worse Saturday when the new 5G high-speed wireless network is rolled out.

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An aviation expert who explains how that may impact your summer travel.

Thelma and Todd Joiner flew to Georgia a week ago. They were supposed to be back home in Makakilo early Tuesday evening. Instead they’re stuck at the airport in San Francisco.

“We got here like around 12, I believe,” Thelma Joiner said. “And then the flight got delayed at 1:30. And then it was 3:30, 5:36, and 8:10, 8:27. And now 10 p.m.”

Joiner said they were first told there was no pilot, then the next cancelation they were told their flight was waiting for a flight attendant.

About an hour after we spoke she got a text from United Airlines canceling her 10 p.m. flight.

The text said:

“We’re sorry to let you know we’ve canceled flight UA300 from San Francisco to Honolulu because your crew did not have sufficient off-duty/rest time required by federal law.”

Their next scheduled flight is Friday.

Ongoing staffing shortages are just one issue plaguing airlines.

Travel woes could get even worse starting Saturday if airplanes aren’t properly retrofitted with new equipment when the new 5G network is rolled out, 

According to the Federal Aviation Administration’s website:

“These frequencies can be close to those used by radio altimeters, an important piece of safety equipment in aircraft. To make sure that this does not lead to hazardous interference, the FAA requires that radio altimeters are accurate and reliable.”

Aviation expert Peter Forman said that raises concerns.

“There’s a problem of a potential conflict with the 5G signals,” Forman explained. “So they have to put on filters to reduce the chance that there’s any interference between the 5G and radar altimeter signal.”

Forman said the altimeter is used when planes are within 200 feet of the ground in bad visibility.

The good news is it doesn’t directly affect Hawaii’s airports. A map shows the airports across the United States that will be impacted.

“But passengers can be affected on flights to the mainland,” Forman said. “And, you know, if there is an issue at a particular airport, do let’s say fog in the LA or San Francisco, that can backup flights and affect the mainland flights coming to Hawaii.”

According to the U.S. Department of Transportation, 80% of the planes that serve the U.S. have already been retrofitted. But that means 20% still aren’t.

Hawaiian Airlines and Southwest both say they do not expect any issues.

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In a statement, Airlines for America said:

“A4A member carriers are working diligently to ensure fleets are equipped with compliant radio altimeters, but global supply chains continue to lag behind current demand. Carriers have repeatedly communicated this reality to the government. In order to avoid potential disruptions in the future, NTIA and the FAA must better coordinate with each other to ensure a common understanding of safety and equipage impacts. Nevertheless, thanks to careful planning, A4A member carriers are confident in their ability to maintain the integrity of their schedules, despite the impending deadline. While our industry strongly supports 5G deployment, safety is—and always will be—the top priority of U.S. airlines.”